Addressing the Problem with a Worn Prop Shaft

[Roverworks Canberra]

The Discovery 2 has a unique front prop shaft connecting the transfer box to the front diff. It has a "cardan joint" on the transfer box end - two universal joints right next to each other. This allows for a greater range of movement with a lesser angle on each universal joint.

The problem with these is that when they wear out, they let go, and all manner of evil happens under the car. The end of the shaft whips around until it falls off, things do fall off, and as we can see, damage to important parts of the car then occur. This unfortunate vehicle has had the gearbox casing cracked, there is a mysterious clunk in the transfer box when you try to push the vehicle, the high low selector cable on the transfer box has been destroyed, and holes have been bashed through the floor and through the chassis rail. There was a lot of force required to knock that hole through the chassis rail.

Read more here:
Unique Front Prop Shaft of Discovery 2 (http://roverworks.com.au/news/prop-shaft-discovery-2/)

[p38arover]

The term Cardan Joint (named after the inventor, Cardano) is variously known as a Hooke's Joint or Universal Joint. Unfortunately, you will find that many posts on the 'net call it a "cardinal joint".

[Slunnie]

It's called a "Double Cardan" joint. The Yanks also call it a CV joint, although its not a CV joint as we know them. The purpose of the Double Cardan has more to do with oscillations rather than available angles. They are a pretty common part, they're not unique at all. The Discovery 2 just runs a 1300 DC joint, many people swap them out now for one size up which is a 1310 size.

I've read a lot about what people think cause the failure, but my opinion is that the failures begin in that centre bearing, then the uni bearings fail and then the entire joint fails.

[Jason789]

Thanks for the pics Roverworks Canberra, which show the damage that can be caused by this common problem if it it not looked after soon enough.

[eckolsim]

The biggest threat to the double Cardan Joint on a D2 is the aircon drain above it. The constant water feeding into the joint kills it.

Slunnie, a 6" lift doesn't help either. Hope you're well.

[d2dave]

The biggest threat to the double Cardan Joint on a D2 is the aircon drain above it. The constant water feeding into the joint kills it.


I don't subscribe to this theory for two reasons. On mine the water does not drip directly onto it and secondly what about driving in rain and doing river crossings?

[justinc]

Have seen a few v8 d2 ones fail from what I think is the excessive heat from the cat less than 100mm away... I also don't think the a/c evaporator drain position has much to do with it. I place the blame squarely on the lack of serviceability/ greaseability of the joints' components.

Jc

[justinc]

The term Cardan Joint (named after the inventor, Cardano) is variously known as a Hooke's Joint or Universal Joint. Unfortunately, you will find that many posts on the 'net call it a "cardinal joint".


Hi ron. Hope all is well?

The word cardinal can be used to describe the sinful nature of the designer of these at gkn driveline. No grease points is just plain criminal neglect for use in a 4wd. After the publication of those photos from RW Canberra, I suppose we could actually rename them the 'carnage' joint!

Jc

[slug_burner]

I know them as cardan joints and although different to the ball and cage cv they do produce a constant velocity joint. I think the greater the angle on a universal joint the greater the variation in rotational speed of the shaft the other side of the joint from the driven shaft. Therefore the cardan joint is used to eliminate vibration resulting from the pulsing of rotational speed of universal joints, the greater the angle more that the cardan joint is required.

At over 200km mine had not failed but it was changed as required by the service schedule.

[d2dave]

I know them as cardan joints and although different to the ball and cage cv they do produce a constant velocity joint. I think the greater the angle on a universal joint the greater the variation in rotational speed of the shaft the other side of the joint from the driven shaft. Therefore the cardan joint is used to eliminate vibration resulting from the pulsing of rotational speed of universal joints, the greater the angle more that the cardan joint is required.

At over 200km mine had not failed but it was changed as required by the service schedule.

I believe that Double Cardan is the correct name.
A cardan joint is not used to alleviate the angles, it is used because the two mating flanges are not parallel. If they are parallel, large angles can work ok with standard uni joints.

[slug_burner]

Yes double cardan, which implies that the universal joint we know is a cardan joint.

Yes the use of the cv joint then allows for the flange surfaces not to be parallel.

Tom Wood's custom drive shafts web page has some info on selecting the type of joint.

[rrturboD]

I understand worn joints are repairable rather than just using a new shaft replacement.
I have looked on AULRO for repair advice and parts required, but must be searching for the wrong things.
Advice please.

[Slunnie]

I understand worn joints are repairable rather than just using a new shaft replacement.
I have looked on AULRO for repair advice and parts required, but must be searching for the wrong things.
Advice please.
Check out the good oil.

http://www.aulro.com/afvb/good-oil/61452-d2-prop-shaft-secrets-ujs-double-cardan-joints.html

[rrturboD]

Just what I had been looking for, thanks, but 32 pages.....
I'll add a new entry when I get my bits, because some of the part numbers have changed.

[PhilipA]

Mario at Roverlord was advertising kits a few weeks ago, so I assume he would still be able to supply them, so maybe you don't need to research too much.
Regards Philip A

[Slunnie]

Just what I had been looking for, thanks, but 32 pages.....
I'll add a new entry when I get my bits, because some of the part numbers have changed.
Scroll down on the link I gave you. Check out Urban Panzers link and Clubagreenies post.

[p38arover]

A cardan joint is not used to alleviate the angles, it is used because the two mating flanges are not parallel. If they are parallel, large angles can work ok with standard uni joints.

A Cardan Joint is the same as a Hooke's Joint or universal joint - same thing, different names.

[madtom]

I don't think, there is a problem with the prop shaft design, only with poor maintenance. I get some broken prophafts and all had rusted and worn one of the universal joints. Central bearring was in much better condition. And in all shafts, the 3rd universal joint (at front diff side) was already replaced with a new one.
The maintenance of double joint is a bit harder, but it is still just maintenance.
Second problem is - original universal joints have no grease point, so everyone thinks, no maintanance is necessary. This is totally wrong.

[d2dave]

I don't think, there is a problem with the prop shaft design, only with poor maintenance. I get some broken prophafts and all had rusted and worn one of the universal joints. Central bearring was in much better condition. And in all shafts, the 3rd universal joint (at front diff side) was already replaced with a new one.
The maintenance of double joint is a bit harder, but it is still just maintenance.
Second problem is - original universal joints have no grease point, so everyone thinks, no maintanance is necessary. This is totally wrong.

So if there are no grease points how is maintenance done?

[PhilipA]

So if there are no grease points how is maintenance done?


Gee I am hardly game to post that in this case maintenance perhaps maybe should be replaced with "inspection". ( to be precise)

I inspect mine before any long trip, by lying underneath and looking for any rust marks, grabbing each element both ends and seeing if there is any play.

IMHO, the ones that go "suddenly" do no such thing as a uni joint will soldier on for months , maybe years when it is stuffed.
I was going to say it takes cloth ears and no appreciation of differences in vibration not to know when a uni is on the way out but I don't want to offend anyone , so I won't.
Just for that my shaft will probably let go next week.
Regards Philip A

[d2dave]

Dmdigital gave his a thorough inspection before he left Gove and all looked and felt fine. Just Nth of Alice and with no warning it let go, punching a hole in his transmission.

I estimate that I have probably changed in excess of 500 uni joints in my life.
Now I am only talking single joints here and I have seen 'em all. Many a joint I have changed, when doing a clutch, and upon removal of the tailshaft, found the universal joint to be in poor condition with no symptoms showing. (partially seized but no drive vibration)

However I have never seen one completely let go without lots of prior warning that something was not right.

Now it does have me wondering whether a DC having two joints so close together, will not show up early developing symptoms and then go bang.

[Fast Freddie]

Cardan Joint:
Cardan joint - Wikipedia, the free encyclopedia (http://en.wikipedia.org/w/index.php'title=Cardan_joint&redirect=no)
Double Cardan Joint
Constant-velocity joint - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Constant-velocity_joint#Double_Cardan)

[Fast Freddie]

So if there are no grease points how is maintenance done?

I've read heaps of valuable information on here about this subject, including all of the monster post that Pedro started (to quote Georgesadlik: "that's normal, right?)
I don't think that just 'inspecting' from under the car has proven a reliable method of determining whether they are about to come to pieces.
My car has done almost 120kks and I'm going to buy four rebuild kits, strip both prop-shafts, press out the old bearings and replace them all.

When the old ones are on my bench, I'll know whether they were cactus.
When I put the shafts back in, I'll feel confident that they are not about to die (I don't have any lift or unusual power characteristics).
If they do die inside the the next 100kks, I'll be mad as hell and buy replacement, heavy-duty, bits from the US

[madtom]

Maintenance of UJ is not juts greasing them. It is also checking their play and checking the seals. UJ with some play or worn seal must be replaced.
But lot of people told me, that no grease point = no maintenance needed. But the only difference between UJ with grease point and without is the grease inside and mud seals. The rest is the same. And when the seal is gone, grease is washed out quickly and the internals of UJ is rusting. So it is good idea to check the UJ.
2 day ago a get a phone from friend with D2 - his car makes some unusuall noise, after some quick check, he found UJ one front diff worn and rusty. So he removed the fron shaft for repair and found all UJ worn - without grease. He was able to detect this problem with shaft still on car - just carefull look on and test with a pry bar for excessive play. The shaft is still originall - after 12 years and more than 200 000km. I think, this is wery good result. Standard cheap UJ normally survive 20 000km or less. UJ with better seal, more than twice longer at least. But they are a bit more expensive and not in stock, so we have to wait for them for a few days.

[Epic_Dragon]

I need to check these joints on mine. I had loose drive shaft bolts so think checking everything for wear is a good idea (326000 kms and not sure if its ever been replaced in its life :))

[Disco Muppet]

Guys (and girls).
Lets keep this on topic.
Some posts have now been removed from this thread.
Keep in mind that when dealing with items or practices of a technical nature, the correct terminology is important to ensure you get accurate advice.
That said, lets keep it friendly.
There are no points given out this round, but if it continues or spills into other areas that may change.
Cheers
Muppet